Aatrox, the Darkin Blade

0: If Aatrox, the Darkin Blade would be exiled, bring him back into play if you sacrificed a creature or planeswalker of cmc 6 or more.
+1: Aatrox, the Darkin Blade deals 4 damage to any target. Put a combo counter on Aatrox, the Darkin Blade. He keeps combo counters on him in exile.
+2: If Aatrox has at least 3 combo counters on him, remove X and deal damage equal to twice the amount of combo counters on him to any target